Heath Consultants Heath Data Recorder (HDR) - Manual (Page 7)

7
Mounting & Installation
Housing Configuration
The HDR is available in many configurations. The maximum number of integral sensors is as follows:
• Pressure: up to three
• Temperature probes: two (plus internal case temp)
The housing type will determine whether sensor connections are made from the bottom or rear of the instrument as
follows:
• Wall/Panel mount: bottom connect
• 2” pipe mount: bottom connect
• Portable: rear connect
Pressure Connection(s)
Connect up to 3 pressure inputs to the 1/4” NPT female connectors located on the bottom or back of the HDR housing.
After piping is complete, check all connections to ensure that no leaks are present.
Temperature Probe(s) Installation
If equipped, up to 2 standard 6 foot long temperature probes (6” x 1/4” OD) may be used, and should be installed into the
appropriately sized thermowell filled with a thermo conductive medium such as glycol or alcohol. Insert the temperature
probes into the thermowells through the standard 1/4” inch NPT male gland (provided) until the tip of the probe reaches
the bottom of the well. Secure excess armor cable length of the probe.
It will be necessary to isolate the pressure and temperature connections to the pipeline, so as not to disturb the cathodic
protection system.
Electrical Installation
NOTE: Refer to drawing MTM-308-1 for field wiring requirements for external power and modem connections to
maintain intrinsic safety.
The HDR unit must be earth grounded to maintain safe operation and warranty.
The ground stud of the HDR (located on the bottom of the instrument) must be connected to a suitable known external
earth ground (usually a dedicated ground rod and NOT AC ground). All of the major components in the HDR are
bonded together and connected internally to this groundnut. It is required that grounding be performed, especially when
an external modem and/or external power supply (which requires a dedicated ground rod in close proximity to the safe
area) is used. All cabling connecting to the HDR must be shielded with all shields tied to case ground.
For multiple device interconnections (modems, power supplies etc.) the groundnut of the HDR must be tied directly to this
same (safe area) ground rod rather than having a separate ground rod of its own.
The American Gas Association recommends grounding all electronic field devices to a driven ground rod. This will help
protect the device from transients including lightning and power surges on the pipeline.
To reduce the possibility of “secondary” lightning strike damage (damage caused by static electricity fields in the
immediate area), the above precautions are required. However, these precautions cannot prevent damage to an instrument
that receives a “direct” lightning strike.